1. Field of the Invention
The instant invention relates to a high frequency transistor power amplifier comprising a plurality of power transistors disposed in an annular arrangement such as used, for example, as the final stage in radio or television transmitters.
2. Description of the Prior Art
High frequency transistor power amplifiers of this kind are known (U.S. Pat. No. 4,641,107, German DE-OS 32 07 711, incorporated herein by reference). With these known power amplifiers, not only a separate input matching circuit is associated with each individual power transistor, but also a separate output matching circuit. In other words, resistance transformation and decoupling are effected for each individual transistor both at the input and output ends. Where high power is at stake, such as 1000 watts or more, the structure of the output matching circuits and coupling means for combining the individual transistor contributions is quite complicated technically and rather bulky, apart from being expensive.